Speed regulator for machine guns



Dec. 31, 1929.

C. PF EIFFER SPEED REGULATOR FOR MACHINE GUNS Filed March 23. 1929 W 7% 3 3 E V l IL .J e awa?. .U me-: a m :ww/4 A `:.tlflunv MW nllli w HHH a F m. 1 w

Patented Dec.. 3i, 1929 T T E Hei@ CHRISTIN-PFEIFFER, OF `HARTFORIL CONNECTICUT, ASSIGNOR T0 COLTS YATENT FIRE ARMS MANUFACTURING CO., OF HARTFORD, CCNNECTICUT, .A CORPORATION F CONNECTICUT SPEED REGULATOR FOR MACHINE GUNS Application led March 23, 1929. Serial No. 349,430.

firing may be so rapid when the gun is being voperated withits full automatic action as'to be positively disadvantageous. The'rate of firing may be so rapid that the shooter cannot properly aim his gun, with the result that 'ammunition is wasted and that the succession of'shots is so rapid that the gun heats up too rapidly and that the rifling in the barrel Wears out too quickly. It has, therefore, been found advisable to provide means to retard the rate of firing by ensuring a lapse of time between successive shots greater than the time required for the usual recoil and return to battery of the recoiling parts.

In my copending application for Speed regulator for machine gun, Serial No. 205,- 210 filed July 12, 1927, I have shown a speed regulator adapted for retarding the rate of' firing of a machine gun and adjustable to provide different retarding effects. vThe present invention relates to amechanism of the general type disclosed in the said application but differing in certain important respects.

One of the objects of the present invention is to provide a speed regulator of the type described which is adapted to form a p'ermanent part of the firearm instead of being only an attachment therefor as shown in the above mentioned application. In accordance with the invention the provision is made for changing the effective length of the regulating lever to vary theretarding effect.

Another object of the present invention is to provide an improved arrangement of parts whereby the same brake or retarding mechanism which serves. to absorb the recoil of the barrel and barrel extension may be also used to effect the retarding of the breech bolt. v Other objects of the invention will be apparent from' the following specification and claims.

y In the accompanying drawing I have shown one embodiment of the invention but it will be understood that the drawing is for illustrative purposes only and is not to be construed as defining or limiting the scope of the invention, the claims forming a part of this specification being relied upon for that purpose.

Of the drawing:

Fig. 1 is a fragmentary longitudinal sectional view showing the rear part of a firearm embodying my invention.

Fig. 2 is a view similar to Fig. 1 but showing the movable parts in recoiled positions.

Fig. 3 is a rear View of the firearm with the rear plate thereof removed, this view being taken along the line 3--3 of Fig. 2. Y

Figs. 4 and 5 are perspective views respectively of the main and upper portions of the regulating lever, these views being taken from the left side.

Fig. 6 is a fragmentary rear view similar to Fig. 2 but showing the breech bolt `moved forward and at the point of release from the regulating element.

Fig. 7 is an enlarged fragmentary longitudinal view through the cylinder, the forward part of the piston being shown in elevation and the rear part thereof being shown in section.

In the accompanying drawing I have illustrated a firearm in many respects similar to that disclosed in Patent 1,628,226 issued May 10, 1927 to John M. Browning. Reference may be had tothe said patent for various details of construction of the firearm not herein otherwise disclosed.

'As shown in the drawing the firearm comprises a main casing 1 substantially rectangular in transverse outline as indicated in Fig. 3. The casing is closed at the rear by means of a plate 2 which is removable in the upward direction being normally held in place by means of a latch 3. Connected with the plate 2 are handles 4 wlierebythe gun may be controlled and adjusted. Also carried by the plate 2 is a trigger 5 which' is adapted to engage a trigger lever 6 adapted to operate as disclosed in the said patent.

The firearm is provided with the usual barrel, (not shown) andwith the usual barrel extension 7 the said barrel and barrel extension being movable rearward yupon recoil.

The is further provided with a breech block 8 which is movable rearward upon recoil, a reaction spring 9 being provided for returning the breech block in the forward direction. The breech block is moved to its rearward position asshown in Fig. 2 partly by the force of recoil and partly by the pivoted accelerator 10, which is turned in the' clockwise direction by the rearward moving 10 barrel extension and which enga es the forward facing shoulder 11 on the reech bolt to snap or throw the breech bolt rearward. f The recoil of the barrel and barrel extension is absorbedby a buffer or brake mechanism which comprises a cylinderand'apiston movable therein, the cylinder containing a suitable liquid such as oil. The cylinder is shown at l12 and is mounted within a supporting member 13 secured in place in the main casing 1. Longitudinally movable within the cylinder 12 is a piston 14 connected with a forward extending piston rod 15. This piston rod extendscthrough a stuiiing box 16 formed in a transverse wall or head 17 at the forward end of the cylinder 12. The

piston rod 15 is provided with a head 18 having interlocking engagement with a rearward f extension 19 on the barrel extension 7. Thus the piston. and piston rod are connected for an longitudinal movement with the barrel and barrel extension. Connected with the head 18 and slidably movable inthe bore of the supporting-member13 is a washer 20. A coil' spring 21 is provided which surrounds the piston rod 15, this piston rod abutting at its forward end against the washer 20 and abutting atits rearward end against the cylinder head 17. f

The piston 14 is constructed as shown in the said patent, being provided with longitudinal noles 14a and with a valve member 22 which-is movable toward and away from the main body .of the piston to open and close holes 14a therein.

Upon recoil the barrel and barrel extension move rearward.' As stated the rearward movement is resisted and retarded in part by the coil sprin 21 which presses against the washer 20 an in part by the piston 14 moving within the cylinder 12. During rearward movementof the piston the valveme-mber 22 closes the holes 14a thus causing resistance to rearward movement. When the parts reach theirrearwardpositions as shown in Fig. 2

the barrel and barrel extension are held by the engagement of the accelerator 10 with a shoulder 23 on the projection 19. They are so held until the breech block moves forward far enough forl the shoulder 11 thereof to e0 strike the accelerator and move it toward the front, thusdisen'gaging it from the said shoulder 23. Thereupon the barrel and barrel extension are moved forward to their normal v.firin positions by means of the spring 21 wh'c presses against the washer 20. During forward movement the valve member 22 1s separated from the piston proper, thus permitting oil'to pass freely through the 'holes' one side of the main casingl within a re cess 25 formed in the supporting member 13. The lever 24 is pivoted to the said member at 26. lThe lever 24 has an upper end portion 27 which is adapted to engage with a suitable projection or shoulder 28 formed on the breech bolt 8, the construction being such that the said end portion of the lever is in engagement with the breech block during the initial part of its counter-recoil movement and swings about its pivotal axis out of such engagement to permit the breech block to complete its forward counter-recoil movement independently of the lever. The disengagement of the breech block from the lever will be apparent from an inspection of Fig.

6. The lever 24 is connected with a suitable retarding means to be presently described in detail with the result that the said lever of the lever may be changed so as to change.

the position at whih the breech block is disengaged therefrom. Preferably I accomplish this' by constructing the upper end portion 27 of the regulating lever as a separate portion which is transversely pivoted to the main portion at 29. A screw 30 is rotatably mounted in the main body of the lever 24,

this screwv being` provided with a nut 31" which is held against rotation. The screw 30 has secured to it a bushing30a which prevents endwise movement. A lug 32 on the lever portion 27 engages the nut 31. By turning the screw 30 and moving the nut 31 the said end portion 27 of the lever may be adjusted about kitspivotal axis at 29 to thereby change the effective length of the lever. Preferably the construction is such that the end portion 27 of the lever may be moved entirely out of the path of the lug 28. Thus the retarding action may be entirely eliminated.

Preferably the end portion 27 of the lever is in the form of a latch normally held in its operative position by merknsof a spring 33. When the said portion 27 is in the form of a 4mit the adjustment of the screw to change the retarding action l preferably providenmeans whereby the screw may be rotated without removing the rear plate 2. As illustrated l provide a screw driver 3a which is rotatably mounted in a suitable 'aperture in the rear plate 2 and Which is normally in alignment with the screw 30. The screw driver is normally pressed rearward by means of a spring and it is provided at its rear end with a knob 36. When it is desired to rotate the screw to adjust the retarding action the screw driver is pressed forward in opposition to the spring 35 until the screw is engaged. Then by turning the knob 36 the screw can be rotated in either direction as required.

ln accordance with another phase of the invention I effect the retarding of the movement of the breech block by the same mechanism which serves to retard the rearward recoil movement 0f the barrel and barrel eX tension. The details of the mechanism for accomplishing this result may be varied but preferably and as shown I accomplish this result by so mounting the cylinder 12 that'it is longitudinally movable. rlhe cylinder is normally held in its rearward position as shown in Figs. 1 and 2 by means of the spring 21. The cylinder 12 is connected with the regulating element or lever 24 and for this purpose the said lever is provided with a pin 37 which abuts against a rearward facing shoulder 38 on the exterior of the cylinder. It will be obvious that when the regulating lever is moved forward by the breech bolt from the position shown in Fig. 2 to the position shown in Fig. 6 the engagement of the pin 37 'with the shoulder 38 of the cylinder will move the said cylinder forward as indicated.

The cylinder 12 preferably has its rear portion 39 formed with an interior smaller diameter than the forward portion thereof,

and there is also provided on the piston rod 15 a second piston LlO'which is of smaller diameter than the piston 14. As shown the piston 14 is formed with a rearward extending sleeve 14b which surrounds the piston rod 15 and upon which' the piston 40 is mounted. The piston 40 is adaptedto lit the reduced rear portion 39 of the cylinder. The piston 4.0 has longitudinal holes 20 with a valve member 41 which cooperates w"th the said holes. When the cylinder 12 and is provided is moved forward relatively to the piston 40 the holes 40a are closed by the valve member 41 with the result that forward movement of the cylinder is resistedand retarded, thus resisting and retarding the forward counterrecoil movement of the breech block. How` f ever, when the breech block is disengaged as shown in Fig. G, the cylinder 12 is immediately returned in the rearward direction by means of the spring 21, this rearward movement taking place freely by reason of the movement of the valve member 4l away from Athe pistontOihus allowingrrthe free I passage of oil through the holes 40a.

From the foregoing description it will be apparent that a single mechanism servesv to resist the recoil movement of the barrel and barrel extension and also to retard the initial counter-recoil movement of the breech block. Upon recoil of the barrel and barrel extension the piston 14: moving within the cylinder 12 offers resistance and at the same time additional resistance is offered by the spring 2l. During the initial counter-recoil movement of the breech bolt the resistance is offered by the same cylinder l2 cooperating with the piston 40 and the spring 2l is further compressed as shown in Fig. 6. Subsequently the spring 21 serves to return the cylinder and the regulating lever to their rearward normal positions and to return the barrel and barrel extension to their forward normal positions.

What I claim is:

1. The combination in an automatic {irearm of a recoil-actuated reciprocating member, a regulating lever pivoted for movement about an axis perpendicular to the direction of reciprocation, the said lever automatically engaging thevsaid reciprocating member during the initial part of its counter-recoil movement and swinging about its pivotal axis out of engagement therewith to permit the reciprocating member to complete its counterrecoil movement independently of the lever, means for changing the effective length of the lever to thereby change the position of disengagement from the'reciprocating ineinber, means connected with the said regulating lever for thereby retarding the said initial part of the counter-recoil movement of thereciprocating member, and automatic means acting after disengagement of the reciprocating member. for returning the said regulating lever to its position of initial engagement with the said member.

2. The combination in an automatic firearm of a recoil-actuated reciprocating member, a regulating lever pivoted for movement about an axis perpendicular to the direction of reciprocation and comprising an end portion transversely pivoted to the main portion, the said end portion of the lever automatically engaging the said reciprocating member during the initial part of its counter-recoil movement and swinging about the main pivotal axis of the lever out of engagement with the reciprocating member to permit the said member to complete its counterrecoil movement indepndently of the lever, means for adjusting the end portion of the lever about its own pivotal axis to thereby change theneffective length of the lever and thus change the position of disengagement from the reciprocating member, means connected with the said regulating lever` for therebyl retarding the said initial part of the ber, a regulating lever pivoted for movement about an axis perpendicular to the direction of reciprocation and coiprising an end portion transversely pivote to the main portion,

'the said end portion of the lever automatical-A ly engaging the said reciprocating member during the 1n1t1al part of its counter-recoil movement andswingmg aboutthe mam -pivotal axis of the lever out o f engagement withthe reciprocating member to. permit the said member to complete its counter-recoil movement independently vof. the lever, a screw on the lever for adjustingthe end `portion thereof about its own pivotal axis to thereby change the ei'ective length of the lever and thus change the position ofdisengagement from the vreciprocating member, means carried by the firearm independently of the lever for vengaging the said screw to rotate 1t, means connected with the said regulating lever( for thereby retarding the saidinitial part of the`counter-recoil movement of the reciprocating member, and automatic means acting after disengagement of the reciprocating member for returning the said regulating leverto its position of initial engage-- ment with the said member.y

'5. A combination `as set forth in claim 4, wherein the lir'earm comprises a main `casing and a removable rear `plate therefor, and

' wherein the regulating lever is mounted on the main casing and the screw rotating means is mounted on the removable rear plate.

6. In an automatic iirearm, the combination of a recoil-actuated reciprocating'barrel extension, a reciprocating breech block, and a common'means serving to retard the recoil movement of the barrel extension and to retard the counter-recoil movement of the breecltblock.

7. In an automatic lirearm, the combination of a recoil-actuated reciprocating barrel extension, a reciprocating breech block,l a regulating element automatically engaging the breech block during the initialpartof its counter-recoil movement and automatically disengaged therefrom immediately thereafter to permit the breech block to complete its counter-recoil movement indepndently of the regulating element, and a common means for retarding the recoil movementof the barrel extension and for retarding the counter-recoil movement of the regulating lever and the breech block. y

8. In an automatic irearm, the combination of a recoil-actuated reciprocating barrel extension, a reciprocating breech block, and a common means comprising a cylinder and apiston therein relatively movable with respect to each other for retarding the recoil movement ofthe barrel extension and for retarding the counter-recoil movement of the v breech block.

9. In an automatic firearm, the combination of a recoil-actuated reciprocating barrel extension, a reciprocating breech block, and a retarding means comprising a c lin'derand a cooperating piston both movable, one of them serving to retard the recoil movement of the barrel extension and the other of them serving to retard the counter-recoil movement ot' the breeclrblock.

10. In an automatic firearm, the combination of a recoil-actuated reciprocating barrel extension, a reciprocating breech block, a.

regulating element automatically engaging the breech block during the initial part of its counter-recoil movement and automatically disengaged therefrom immediately thereafter web to permit the breech block to complete its counter-recoil movement independently Y of the regulating element, and a retarding means comprising a movable piston connected with the barrel extension and a movable cylinder enclosing the piston and connected with the regulating element.

11. Inan automatic firearm, the combination of a recoil-actuated reciprocating barrel extension, a reciprocating breech block, a

regulating element automatically engaging the breech block during the initial part of its counter-recoil movement and automatically disengaged therefrom immediately thereafter to permit the breech block to complete its counter-recoil movement independently of the regulating element, means for retarding the counter-recoil movement of the regulating element and the breech block, and a common means forretarding the recoil movement of the barrel extension .and for returning the regulating element to its position of initial engagement with the breech block.

12. In an automatic firearm, the combination of a recoil-actuated reciprocating barrel extension, a reciprocating `breech block, a

forwardl movable cylinder connected with the breec block to retard the counter-recoil movement thereof, a rearwardly movable piston in the cylinder connected with the barrel extension to retard the recoil movement thereof, and a spring serving to additionally retard the forward counter-recoil movement of the cylinder and breech block and also to additionally retard the rearward recoil movement of the barrel extension and piston.

13. In an automatic firearm, the combination of a, recoil-actuated reciprocating barrel extension, a reciprocating Ybreech block2 a regulating element automatically engaging the breech block during lthe initial part of its counter-recoil movement and automatically disengaged therefrom immediately thereafter to permit the breech block to complete its counter-recoil movement independently of the regulating element, a retarding means comprising a movable piston connected with the barrel extension and a movable cylinder enclosing the piston and connected with the regulating element, and a spring serving to additionally retard the recoil movement of the barrel extension and also serving to re- -turn the movable piston and the regulating lelement to their initial ositions.

14. In an automatic rearm, the combination of a recoil-actuated reciprocating barrel extension, a reciprocating breech block, a longitudinally movable cylinder connected with the breech block and having its rear portion of smaller diameter than -its forward portion, and a longitudinally movable piston in the cylinder connected with the barrel extension and comprising two parts adapted to respectively fit the two portions of the cylinder, the forward lar er part of the pistonhaving a valve mem er which permits free forward movement of the piston relatively to the cylinder butcauses resistance to rearward movement and the rear smaller part ofthe piston having a valve member which permits free rearward movement of the cylinder relatively to the piston but causes resistance to forward movement.

15. In an automatic firearm, the combina- 4 tion of a recoil-actuated reci rocatino' barrel extension, a reclprocating reech block, a

transversely pivoted regulating lever auto-4 matically engaging the said breech block during the initial part of its counter-recoil movement and swinging about its pivotal axis out of engagement therewith to permit the breech block to `complete its counter-recoil movement independently of the regulating lever, a longitudinally movable cyllnder connected with4 the regulating lever and having'its rear portion of smaller diameter than its forward portion, and two longitudinally movable pistons' in the cylinder connected with the barrel exl tension and adapted to respectively fit the two portions of the cylinder, the forward larger piston having a valve member which permits free forward movement of the piston relatively to the cylinder but causes resistance to rearward movement and the rear smaller piston having a valve member which permits free rearward movemment of the cylinder relatively to the piston but causes resistance to forward movement.

' 16. In an automatic firearm, the combination of a recoil-actuated reciprocati barrel extension, a reciprocating breech bloc a longitudinally movable cylinder connected with the breech block and having its rear portion of smaller diameter than its forward portion, two longitudinally movable pistons in the cylinder connected with the barrel extension and adapted to respectively fit the two portions of the cylinder, the forward larger piston having a valve member which permits free forward movement of the piston relatively to the cylinder but causes resistance to rearward movement and the rear smaller piston having a valve member which permits free rearward movement of the cylinder relatively to the piston but causes resistance to forward movement, and a common spring for moving the piston and barrel extension in the forward direction and for moving the cylinder in the rearward direction.

In testimony. whereof I have hereunto set my hand this 21st day of March, 1929.

' CHRISTIAN PFEIFFER. 

